Re: [Bug-xorriso] creating bootable .ISO with multiple methods

[Thomas Schmitt]

Hi,

> EFI encompasses the use of FAT32 for a system partition, and FAT12
> or FAT16 for removable media.

Ah yes. Only FAT32 stuck to my memory.


>  And took me a while to figure out.  The embedded grub.cfg (not
> included in the gist) looks like this:
>
>  search.fs_label RECOVERY root
>  set prefix=($root)/boot/grub

So GRUB2 hops out of the FAT filesystem to find its grub.cfg
but then needs to be told that the ISO is the root ?


Isn't "RECOVERY" a bit too unspecific to serve as id string ?
Other people could come to the idea to have that name for
some filesystem of their computer. Most distro ISOs are
labeled by distro name and version numbers. But that's still
not really unique.

To solve the uniqueness problem, Vladimir once asked me
for -as mkisofs option
  --modification-date=2013030413525500
by which grub-mkrescue can set (and thus predict) the
date string of the ISO filesystem.
As generic command that would be

  -volume_date uuid 2013030413525500

The matching grub.cfg line is said to be

  search --fs-uuid --set 2013-03-04-13-52-55-00

(Looks like a different syntax than in your grub.cfg,
 though.)

I understand that GRUB2 maps the ISO 9660 modification
date string to UUID because this is the best approximation
of a unique id in a vanilla ISO 9660.
(We could of course introduce a dedicated storage location
 for such a string. Dunno whether Vladimir did not want to
 depend on non-vanilla stuff or whether he wanted to re-use
 existing GRUB2 code for retrieving the UUID.)


Have a nice day :)

Thomas